public void clear() {
    if (needsAllocArrays()) {
      return;
    }
    this.firstEntry = ENDPOINT;
    this.lastEntry = ENDPOINT;
    // Either both arrays are null or neither is, but we check both to satisfy the nullness checker.
    if (predecessor != null && successor != null) {
      Arrays.fill(predecessor, 0, size(), 0);
      Arrays.fill(successor, 0, size(), 0);
    }
    super.clear();
  }

  /*

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An Iterator implementation which draws elements from a queue, removing them from the queue as it
 * iterates. This class is not thread safe.
 */
@GwtCompatible

import java.util.AbstractList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * An object which joins pieces of text (specified as an array, {@link Iterable}, varargs or even a
 * {@link Map}) with a separator. It either appends the results to an {@link Appendable} or returns

org.checkerframework.checker.propkey.qual
org.checkerframework.checker.regex
org.checkerframework.checker.regex.qual
org.checkerframework.checker.signature
org.checkerframework.checker.signature.qual
org.checkerframework.checker.signedness
org.checkerframework.checker.signedness.qual
org.checkerframework.checker.tainting
org.checkerframework.checker.tainting.qual
org.checkerframework.checker.units
org.checkerframework.checker.units.qual

org.checkerframework.checker.propkey.qual
org.checkerframework.checker.regex
org.checkerframework.checker.regex.qual
org.checkerframework.checker.signature
org.checkerframework.checker.signature.qual
org.checkerframework.checker.signedness
org.checkerframework.checker.signedness.qual
org.checkerframework.checker.tainting
org.checkerframework.checker.tainting.qual
org.checkerframework.checker.units
org.checkerframework.checker.units.qual

            </offlineLink>
            <!-- The Checker Framework likewise would claim javax.annotations, despite providing only a subset of the JSR305 annotations, so it must likewise come after JSR305. -->
            <offlineLink>
              <url>https://checkerframework.org/api/</url>
              <location>${project.basedir}/javadoc-link/checker-framework</location>
            </offlineLink>
          </offlineLinks>

 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import java.util.Queue;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates queues, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

 * limitations under the License.
 */

package com.google.common.collect.testing;

import com.google.common.annotations.GwtCompatible;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * To be implemented by test generators that can produce test subjects without requiring any
 * parameters.
 *
 * @param <T> the type created by this generator.

import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.Multiset;
import com.google.common.collect.testing.TestCollectionGenerator;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Creates multisets, containing sample elements, to be tested.
 *
 * @author Jared Levy
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault

 * limitations under the License.
 */

package com.google.common.collect;

import com.google.common.annotations.GwtCompatible;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * A supertype for filtered {@link SetMultimap} implementations.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault